Interactive graphic: SA's drugs of choice

In the Western Cape "tik" or methamphetamine is the problem drug. Tik use is also creeping up in the Eastern Cape. In Gauteng, Limpopo and Mpumalanga, marijuana and heroin are the big two. In KwaZulu-Natal people seeking treatment for heroin abuse seems to be falling, but marijuana is on the rise. Dagga is also the drug of choice in the Free State, Northern Cape and North West.

Although alcohol remains the primary substance of abuse across the country, when it comes to illegal substances, marijuana is the most commonly used among people attending treatment centres.

But there are regional variations in the drugs that are abused in South Africa, research by the South African Community Epidemiology Network on Drug Use (Sacendu) shows. It has been collecting information from a growing network of treatment centres since 1996 so it can monitor the nature and extent of alcohol and drug abuse in the country.

Treatment centres in the Western Cape report that methamphetamine now accounts for about 40% of their patients' overall drug use. This proportion has grown from 20% in 2004. In the Eastern Cape tik was the primary substance of abuse in 20% of patients admitted during the first half of last year, up from 3% in 2006, an increase Sacendu describes as "alarming" in its latest research brief.

In Gauteng and the Northern region - which comprises six treatment centres in Mpumalanga and one Polokwane, Limpopo - the proportion of patients admitted for heroin problems increased from 22% to 29% between between July 2012 and June 2013.

Heroin is the base drug in nyaope, a cocktail that includes marijuana and other substances. Sacendu started to hear about nyaope two or three years ago, said Siphokazi Dada, one of the authors of the report. But it is listed as a primary substance of abuse only in Gauteng and only since the second half of 2012, where it accounts for 4%.

At present it is likely that the primary drug of abuse listed for nyaope users who report for treatment is heroin, Dada said. From the beginning of 2014 Sacendu has started to ask patients exactly what drugs they are using. If they are using cocktails such as Nyaope – or Whoonga, another heroin-based cocktail that is used in KwaZulu-Natal – the reports will record this. This information will only be available in October when the reports for the period January to June 2014 will become available.

Use the infographic below to explore drug use around the country.

(Clarification: A caption has been added to the infographic under the How much is each drug being used chart to show that the numbers reflect the proportion of patients admitted to treatment centres who report using the drugs)